The invention relates to a motor/pump assembly, in particular a main coolant pump, comprising a housing of a rotary pump with conveying means arranged therein, a heat barrier part, a motor which drives the conveying means, and force-transmitting connecting elements between a housing flange of the rotary pump housing and a flange of the motor.
Main coolant pumps of this type designed as motor/pump assemblies have a pressure-resistant housing with integrated suction connection pieces and delivery connection pieces which are fixedly welded to pipelines in a leak-tight manner. The housing has a delivery-side opening for receiving a push-in part comprising a conveying means in the form of a rotating and guiding device, and also a heat barrier part and a motor part. The housing is closed by a pressure cover on the heat barrier part, to which an electric drive motor is coupled, in order to reduce a heat flow from the hot pump part to a motor part which should be kept cool. These parts are held together by connecting elements which are screwed into a flange of the housing and are extended through or past the heat barrier part. Further, the connecting elements extend through a motor flange and, on the side of the motor flange remote from the pump, hold the motor/pump assembly together with the assistance of nuts which bear against them. Such main coolant pumps are installed both vertically and horizontally in a power station. A vertical arrangement, preferably, directly below a steam generator, allows a cost-effective production of this power station part. Also, due to the arrangement below a steam generator, the construction volume in a power station is appreciably reduced.
To improve the availability of a power station, a type of construction of the motor/pump assembly has proved advantageous in which, in the event of maintenance or repair, the connection between the housing and motor part is opened and the motor, which is designed as a push-in part, together with the heat barrier part and the rotating pump part and with any internals in the housing, is withdrawn as a unit from the housing and is removed for maintenance and inspection work.
With regard to large power stations with a generating capacity of more than 800 megawatts, which for reasons of cost are designed as standard power stations, the spatial conditions for pump demounting are often greatly restricted.